Network signaling optimization for light connected mode

ABSTRACT

Various communication systems can benefit from signaling optimization. For example, communication systems including fourth generation (4G) and fifth generation (5G) networks may benefit from network signaling optimization for light connected mode. A method can include identifying, by a device, that a user equipment has left an area. The method can also include starting, by the device, a suspend procedure for the user equipment based on identifying that the user equipment has left the area.

BACKGROUND Field

Various communication systems can benefit from signaling optimization.For example, communication systems including fourth generation (4G) andfifth generation (5G) networks may benefit from network signalingoptimization for light connected mode.

Description of the Related Art

In 4G networks, it may be important to optimize the signaling of userequipment (UEs) which can have intermittent data exchanges and slowmobility. Up to release 13 there were only two ways of configuring a UE.If a UE is kept in radio resource control (RRC) connected mode then theUE can exchange data after inactivity without an initial triggeringsignaling phase, a transition from idle to connected, but then everychange of cell causes RRC extra signaling compared to idle mode, forexample measurement report+RRC handover signaling.

Conversely, if the UE is kept in idle mode then it can move betweencells using cell re-selection but then whenever there is some exchangeof data, there is an RRC triggering signaling phase, to transition fromidle to active.

The signaling above consumes battery or other power. Moreover, anincreasing number of devices engage in frequent short data exchange andhave slow mobility.

3GPP has envisioned in release 14 of LTE a new third way of RRC: lightconnected (LC) mode, whereby the UE can move across the cells of an LCarea doing only cell re-selection instead of doing the classicalsignaling of RRC, such as measurement report and handover signaling. Inwhat the following discussion will call the inter-eNB LC mode, this LCarea extends across more than one evolved Node B (eNB). At the same timethe UE is kept S1 connected to the last serving eNB while in LC mode.This means that when the UE wants to exchange data the followingsignaling happens depending on two cases.

FIG. 1 illustrates data exchange in two scenarios. In the first case,the UE is still under coverage of the last serving eNB1 (anchor eNB) andRRC signaling needed is almost zero. The signaling needed is RRC page inthe eNB1 for mobile terminated (MT) data and the UE response. In FIG. 1,this is shown as a Uu paging from anchor eNB to UE and paging responseto the anchor eNB.

In the second case, the UE has moved outside the last serving eNB1 intoan eNB2 of the LC area. Then for MT data, for example incoming downlinkdata, the last serving eNB needs to send multiple paging messages overX2 towards all the eNBs involved in the LC area. Those eNBs send RRCpaging messages. The UE just sends an RRC resume or paging responsemessage to eNB2 which triggers a network context fetch procedureinvolving S1 and X2 signaling. In FIG. 1, the UE paging response isshown as a Uu paging response on other eNB.

The above approach may provide the RRC savings advantages of RRC idlemode when moving inactive across the LC area and, whenever data needs tobe exchanged, the RRC signaling sent by the UE is limited to this “Uupaging response” message for MT case, as shown at 4 a and 4 b in the tworespective cases.

However, one can see that the approach entails (S1, X2) signaling forthe second case where the UE has moved out of the last serving eNB(anchor eNB), such as X2 paging, and (X2, S1) context fetch signaling.

There are at least eight issues of this approach. According to a firstissue, in order to enable the context fetch and not lose data, the LCarea must be composed of eNBs which all have an X2 link with the lastserving eNB. Thus, the definition of LC area should be per anchor eNBand one needs to configure one LC area per eNB in the network. Moreover,considering that X2 interface can be flexibly added/removed in release12 onwards (X2 removal feature) it becomes complex to have dynamicupdate of LC areas by operations and maintenance (O&M), as LC area of ananchor eNB1 will need to be updated as soon as any of the current eNB2 spart of the LC area removes the X2 connection with eNB1, and even worse,accounting for the fact that an eNB3 neighbour of the LC area needs toinform the eNB1 when it sees the UE moving out of the LC area, as soonas one neighbor eNB3 of any of the current eNB2 s part of the LC arearemoves the X2 connection with eNB1. Thus, the first issue is thatdefinition, configuration and update of LC areas in the network iscomplex to achieve.

The first issue means that the size of LC areas will remain limited.Considering a moving UE, this means the anchor eNB relocation signalingcould happen frequently. Anchor eNB relocation means changing the “lastserving eNB” role above even though no data has been exchanged by theUE. This relocation requires UE to send an RRC message and theequivalent signaling of context fetch over X2 and S1 signalingtriggered.

Thus, a second issue is that for moving UEs, the so-called inter-eNB LCmode will generate extra signaling at every anchor eNB relocationinvolving additional S1, X2 but also RRC messages.

If the UE is no longer under the coverage of the last serving eNB, theanchor eNB will need to page over X2 possibly successively (pagingrepetitions) across the LC area with the following impacts. According toa third issue, there is a need to define a new X2 paging message.According to a fourth issue there is a need to define a new pagingidentifier over X2 and therefore new PO calculation (similar to 36.304).According to a fifth issue, there is a need of huge buffering in anchoreNB for all the UEs it serves being paged in LC mode. According to asixth issue, there is a need of forwarding this huge buffered data overX2 and the last mile, which can be referred to as a tromboning effect(downlink traffic re-injected into the uplink). According to a seventhissue, there can be data loss if the new eNB has no X2 with anchor eNB,and there can be a need to dynamically manage LC areas, as describedabove. According to an eighth issue, there will be an increase ofcontexts in the serving gateway (SGW), always-on, stateful SGW insteadof stateless SGW because the context is kept in the SGW while the UE ismoving across the LC area.

SUMMARY

According to certain embodiments, a method can include identifying, by adevice, that a user equipment has left an area. The method can alsoinclude starting, by the device, a suspend procedure for the userequipment based on identifying that the user equipment has left thearea.

In certain embodiments, a method can include identifying, by a device,that a user equipment has left an area. The method can also includecommunicating, by the device, with an access node of the LC area toinform the access node that the user equipment has left the area.

A method, according to certain embodiments, can include receiving, at adevice, a first area identifier corresponding to a first radio accessnetwork area (respectively access node). The method can also includereceiving, at the device, a second area identifier corresponding to asecond radio access network area (respectively to a second access node)different from the first radio access network area (respectivelydifferent from the first access node). The method can further includedetermining, by the device, that the second identifier is different fromthe first identifier. The method can additionally include generating, bythe device, an indication toward an access node based on thedetermination.

An apparatus, in certain embodiments, can include at least one processorand at least one memory including computer program code. The at leastone memory and the computer program code can be configured to, with theat least one processor, cause the apparatus at least to identify that auser equipment has left an area. The at least one memory and thecomputer program code can also be configured to, with the at least oneprocessor, cause the apparatus at least to start a suspend procedure forthe user equipment based on identifying that the user equipment has leftthe area.

According to certain embodiments, an apparatus can include at least oneprocessor and at least one memory including computer program code. Theat least one memory and the computer program code can be configured to,with the at least one processor, cause the apparatus at least toidentify that a user equipment has left an area. The at least one memoryand the computer program code can be configured to, with the at leastone processor, cause the apparatus at least to communicate with anaccess node of the LC area to inform the access node that the userequipment has left the area.

In certain embodiments, an apparatus can include at least one processorand at least one memory including computer program code. The at leastone memory and the computer program code can be configured to, with theat least one processor, cause the apparatus at least to receive a firstarea identifier corresponding to a first radio access network area(respectively access node). The at least one memory and the computerprogram code can also be configured to, with the at least one processor,cause the apparatus at least to receive a second area identifiercorresponding to a second radio access network area (respectively to asecond access node) different from the first radio access network area(respectively different from the first access node). The at least onememory and the computer program code can further be configured to, withthe at least one processor, cause the apparatus at least to determinethat the second identifier is different from the first identifier. Theat least one memory and the computer program code can additionally beconfigured to, with the at least one processor, cause the apparatus atleast to generate an indication toward an access node based on thedetermination.

An apparatus, according to certain embodiments, can include means foridentifying that a user equipment has left an area. The apparatus canalso include means for starting a suspend procedure for the userequipment based on identifying that the user equipment has left thearea.

An apparatus, in certain embodiments, can include means for identifyingthat a user equipment has left an area. The apparatus can also includemeans for communicating with an access node of the LC area to inform theaccess node that the user equipment has left the area.

According to certain embodiments, an apparatus can include means forreceiving a first identifier corresponding to a first radio accessnetwork area (respectively access node). The apparatus can also includemeans for receiving a second identifier corresponding to a second radioaccess network area (respectively access node) different from the firstradio access network area (respectively access node). The apparatus canfurther include means for determining that the second identifier isdifferent from the first identifier. The apparatus can additionallyinclude means for generating an indication toward an access node basedon the determination.

A computer program product can, in certain embodiments, encodeinstructions for performing a process. The process can include any ofthe above-described methods.

A non-transitory computer-readable medium can, according to certainembodiments, be encoded with instructions that, when executed inhardware, perform a process. The process can include any of theabove-described methods.

BRIEF DESCRIPTION OF THE DRAWINGS

For proper understanding of the invention, reference should be made tothe accompanying drawings, wherein:

FIG. 1 illustrates data exchange in two scenarios.

FIG. 2 illustrates the broadcast by eNB of eNB (access node) identityover the air for all cells of the eNB, according to certain embodiments.

FIG. 3 illustrates the broadcast by eNB cells of a radio access networkarea identity over the air according to certain embodiments

FIG. 4 illustrates signaling involved when a UE moves out of the lastserving eNB, according to certain embodiments or out of the LC areaaccording to some other embodiments. FIG. 4 presents two options: afirst option where the new eNB takes the decision to suspend and asecond option where the anchor eNB takes the decision (and potentiallyincludes a UE ID for suspended state to relay to the UE).

FIG. 5 illustrates signaling involved whenever data needs to beexchanged, according to certain embodiments.

FIG. 6 illustrates a method according to certain embodiments.

FIG. 7 illustrates a further method according to certain embodiments.

FIG. 8 illustrates a system according to certain embodiments.

DETAILED DESCRIPTION

Certain embodiments can improve the approach described above. Forexample, certain embodiments can keep the same RRC signaling savingswhile avoiding the first through eighth issues mentioned above,depending on deployment. Four examples are provided by way ofillustration and not limitation.

According to a first example, every eNB of the network can broadcast aneNB ID identifier over the air in all its cells. The LC mode can be keptfor UEs as in the existing approach as long as the UE is under the lastserving eNB1. Whenever the UE re-selects a cell of another eNB2, whichthe UE can see from the broadcast eNB ID, the UE can send a “locationreport” RRC message to eNB2 which eNB2 propagates to the last servingeNB1 over X2. eNB1 can then trigger a “suspend” procedure similar to theone used in the cellular internet of things (CIoT). eNB1 can send an “51suspend request” to a mobility management entity (MME) which can movethe UE to evolved packet system (EPS) connection management (ECM)-idlestate but the MME can keep a context of the UE, for example suspendedstate of CIoT.

Whenever the UE needs to exchange data, for example in MT, the CIoTprocedure can be reused. For example, the MIME can page the UE and theUE can respond over RRC triggering a context fetch.

This first example may lead to about the same number of signalingmessages but may remove almost all of the issues identified above. As tothe first issue, because the UE is managed by release 13 optimizationsreachability in ECM-idle mode, the first example can avoid thecomplexity of coordinating dynamic LC areas with neighbor eNBs. As tothe second issue, signaling to move to suspended state may happen onlyonce, even if the UE crosses multiple eNBs between two active (i.e.transmission/reception) phases and regardless of whether these eNBs areX2-connected or not. As to the third issue, there is no need to define anew X2 paging message. As to the fourth issue, there is no need todefine a new paging identifier over X2 and therefore new PO calculation,similar to 3GPP technical specification (TS) 36.304. As to the fifthissue, there is no need of any increased huge buffering in anchor eNB,since the buffering can happen in the SGW in suspended state. As to thesixth issue, there is no need of forwarding a huge amount of buffereddata over X2 and the last mile, as the buffering can happen in the SGWin suspended state. As to the seventh issue, there may be no loss ofdata even if no X2 exists between the new eNB and the old eNB, becausedata is buffered in SGW. As to the eighth issue, there is no increase ofcontexts in the SGW due to always-on stateful in SGW. The SGW can remainstateless as in CIoT suspended state

As an alternative, this example can also cover the case where thereceiving eNB2 initiates relocation of anchor eNB from last serving eNB1into receiving eNB2 when receiving the RRC location report message fromthe UE.

The following examples may allow for flexible deployments mixing certainembodiments with previous approaches.

In a second example, in addition to all eNBs broadcasting their eNB ID,the last serving eNB can send a list of eNB IDs to the UE when aninactivity timer expires. The list can correspond to the LC area for theUE. For example, when the UE exits this LC area, the UE can send an RRClocation report. The receiving eNB can then either relocate the anchoreNB or, in an example approach, propagates the location report over X2to the last serving anchor eNB, which can trigger an S1 suspend requestto the MME.

In a third example, the network can be partitioned in areas called radioaccess network (RAN) areas. Each eNB can be mapped to one RAN area andthe eNB can broadcast a corresponding RAN area ID instead of the eNB IDmentioned above. As long as the UE is within the RAN area, the UE maynot be required to send a location report. When the UE moves out of theRAN area ID broadcast by the last serving eNB, then the UE can send anRRC location report. The receiving eNB can either relocate the anchoreNB, or, in an example approach, can propagate the location report overX2 to the last serving/anchor eNB which can trigger an S1 suspendrequest to the MME. When the eNB receives DL data targeted for the UE,it can page the UE in the cells that belong to the RAN area.

This third example can be seen as an extension of the first example,where the first example corresponds to the third example with a RAN areaequal to an eNB.

In a fourth example, the network can be partitioned in areas called RANareas. Each eNB can be mapped to one RAN area and can broadcast acorresponding RAN area ID instead of the eNB ID mentioned above. Thelast serving eNB can send a list of RAN area IDs to the UE wheninactivity timer expires. As long as the UE is within the RAN areacorresponding to the list of RAN Area IDs, the UE is not required tosend location report. When the UE moves out of the RAN areacorresponding to the received list of RAN area IDs then the UE sends theRRC location report; then the receiving eNB either relocates the anchoreNB (like existing solution), or, in an example approach, propagates thelocation report over X2 to the last serving (anchor) eNB which triggersa S1 suspend Request to the MME (new solution). When the eNB receives DLdata targeted for the UE, it pages the UE in the cells that belong tothe RAN area.

Certain embodiments also address the situation in which the receivingeNB, described in the four examples above, takes a decision betweenrelocation of anchor eNB or propagation of location report to anchor eNBover X2 in order to trigger S1 suspend based on one or more of thefollowing criteria: support of the X2 paging, speed of the UE, or loadof the network.

In other embodiments the four examples described above can apply to 5Gsystem. In such embodiments, the eNB can be replaced by 5G RAN node(currently called GNB) and the X2 interface by the interface between twoGNBs.

FIG. 2 illustrates the broadcast of eNB identity over the air for allcells of the eNB, according to certain embodiments. Thus, FIG. 2 cancorrespond to the first or second example discussed above. As shown inFIG. 2, each eNB can send its own identification (ID), for example usinga broadcast or multicast message. Alternatively, the last serving eNBcould communicate to the UE the list of cells it comprises at the end ofthe last active sequence. The list can be sent, for example, over an RRCmessage.

FIG. 3 illustrates the broadcast of RAN area identity over the air forcells of the eNB, according to certain embodiments. Thus, FIG. 3 cancorrespond to the third or fourth example discussed above.

FIG. 4 illustrates signaling involved when a UE moves out of the lastserving eNB, according to certain embodiments.

FIG. 5 illustrates signaling involved with an MT call, according tocertain embodiments. As shown in FIG. 5, at 1 there can be S11 pagingfrom a serving gateway to an MME. The MME can decide the paging in afirst attempt according to R13 paging optimization. At 2, the MME cansend S1 paging to the old eNB and a currently serving eNB. Both eNBs cansend Uu paging at 3. At 4 b, the UE can provide a paging response to thecurrently serving eNB. The eNB can send a context retrieval request at 5b 1 and receive context transfer at 5 b 2.

At 6 b 1, the eNB can send a pathswitch request to the MME. Accordingly,at 6 b 2 the MME can send a modify bearer request to the servinggateway. The serving gateway can begin transferring packet data at 7 bto the eNB and can acknowledge the bearer modification request at 8.1.The MME can acknowledge the pathswitch request at 8.2, and the eNB canalready be prepared to schedule the data provided from the servinggateway.

FIG. 6 illustrates a method according to certain embodiments. As shownin FIG. 6, at 610, all eNBs or other access nodes can broadcast theirown eNB ID to all their cells. This can be done using any desired orknown technique for disseminating information within cells or sub-cellsunder the control of any access node, such as an eNB. At least one ofthese IDs can be received by a user equipment in or near one of thecells, at 615.

A UE first connected to eNB1 can, at 620, re-select to a cell of neweNB2 and can send a message to the new eNB2. This can be a “locationreport” RRC message or other message that provides an indication thatthe UE is undergoing a cell reselection. This message can be received bythe new eNB at 625.

The new eNB2 can, at 630, forward this message to anchor eNB1 over X2.This message can be received by the anchor eNB1 at 635. At 640, theanchor eNB1 can send an “S1 suspend request” to MME. This message can bereceived by the MME at 645. At 650, the MME can move the UE to ECM-idlestate but can keep the context of the UE. At 660, the new eNB2 cansuspend the Uu connection.

Location information about the UE can be forwarded to anchor eNB1 at630, which can be a reason why the eNB1 can, at 640, send the S1 suspendrequest to MME. Based on this message the UE state can be set to idle at650. For the same reason, the new eNB2 can suspend the Uu connection at660. In case of MT data, the MME can trigger S1 paging to return toconnected mode.

Thus, at 670, when it is detected there is MT data to be exchanged, theMME can page the UE by sending S1 paging, thereby triggering Uu paging.The UE can receive the paging at 672. The UE can, at 674, respond topaging to new eNB2 and the new eNB 2 can, at 676, start a context fetchprocedure towards anchor eNB1.

There is an additional option, namely to broadcast an RAN Area ID to allcells of a given RAN area. This can correspond to an area whereRAN-based paging is supported, which can be equivalent to the area wherethe UE may remain in light connected mode.

With this option, the features at 620 through 676 can be executed if thenew eNB is out of the original RAN area. A cell reselection messagerelated to a single RAN area may still be sent for other purposes, butit would not trigger the same processes including the suspensiondescribed above if the RAN area includes both the original eNB and thenew eNB. The example discussed in FIG. 6 can be seen as an example inwhich the RAN area is simply one eNB.

FIG. 7 illustrates a further method according to certain embodiments. Asshown in FIG. 7, a method can include, at 710, identifying that a userequipment (UE) has left a given area. The trigger for thisidentification may be the reception, at 705, of a message from and/orregarding a UE. The message from the UE can be relayed or forwarded overan interface, such as the X2 interface. Alternatively, an access nodethat receives the message from the UE can generate a different messagethat conveys the same information regarding the fact that the UE haschanged areas. The receiving access node can then send the generatedmessage to another access node (here the anchor eNB).

The given area can be the area of just a single access node, such as aneNB, or the area of multiple access nodes or cells. Thus, theidentification that the user equipment has left the area can be made byreceiving an indication from a user equipment that identifies adifferent eNB ID or other access node identifier or a different RAN areaID or other radio access network area identifier. These variousidentifiers, such as eNB ID, access node identifier, RAN area ID, orradio access network area identifier can be examples of an areaidentifier. Thus, for example, an area identifier can include at leastone of an access node identifier or a radio access network areaidentifier.

The method can also include, at 720, starting, such as by deciding ortriggering, a suspend procedure for the user equipment based on theidentification that the UE has left the given area.

The indication provided by the UE and ultimately received in some formor other by the access node at 705 may be autonomously generated by theUE at 740 upon detecting, at 730, that a corresponding broadcast RANarea ID or eNB ID has changed. In a particular example, a RAN area canbe an eNB area and the RAN area ID can be the eNB ID, although in othercases a RAN area can include a plurality of eNB areas.

Certain embodiments can involve at least two alternative approaches.According to a first approach the system can employ X2 paging within alimited RAN area and use the detailed approach set forth, by way ofexample, in FIG. 6, to move fast UEs into suspended state in order toreduce signaling for those UEs. According a second approach, however, X2paging can be fully avoided, thereby minimizing the listed issues fortheir network.

FIG. 8 illustrates a system according to certain embodiments of theinvention. It should be understood that each block of the flowchart ofFIGS. 6 and 7 may be implemented by various means or their combinations,such as hardware, software, firmware, one or more processors and/orcircuitry. In one embodiment, a system may include several devices, suchas, for example, network element 810 and user equipment (UE) or userdevice 820. The system may include more than one UE 820 and more thanone network element 810, although only one of each is shown for thepurposes of illustration. A network element can be an access point, abase station, an eNode B (eNB), a 5G access node, or any other networkelement, such as a primary cell (PCell) base station or a secondary cell(SCell) base station. Each of these devices may include at least oneprocessor or control unit or module, respectively indicated as 814 and824. At least one memory may be provided in each device, and indicatedas 815 and 825, respectively. The memory may include computer programinstructions or computer code contained therein, for example forcarrying out the embodiments described above. One or more transceiver816 and 826 may be provided, and each device may also include anantenna, respectively illustrated as 817 and 827. Although only oneantenna each is shown, many antennas and multiple antenna elements maybe provided to each of the devices. Other configurations of thesedevices, for example, may be provided. For example, network element 810and UE 820 may be additionally configured for wired communication, inaddition to wireless communication, and in such a case antennas 817 and827 may illustrate any form of communication hardware, without beinglimited to merely an antenna.

Transceivers 816 and 826 may each, independently, be a transmitter, areceiver, or both a transmitter and a receiver, or a unit or device thatmay be configured both for transmission and reception. The transmitterand/or receiver (as far as radio parts are concerned) may also beimplemented as a remote radio head which is not located in the deviceitself, but in a mast, for example. It should also be appreciated thataccording to the “liquid” or flexible radio concept, the operations andfunctionalities may be performed in different entities, such as nodes,hosts or servers, in a flexible manner. In other words, division oflabor may vary case by case. One possible use is to make a networkelement to deliver local content. One or more functionalities may alsobe implemented as a virtual application that is provided as softwarethat can run on a server.

A user device or user equipment 820 may be a mobile station (MS) such asa mobile phone or smart phone or multimedia device, a computer, such asa tablet, provided with wireless communication capabilities, personaldata or digital assistant (PDA) provided with wireless communicationcapabilities, portable media player, wearable device, digital camera,pocket video camera, navigation unit provided with wirelesscommunication capabilities or any combinations thereof. The user deviceor user equipment 820 may be a sensor or smart meter, or other devicethat may usually be configured for a single location.

In an exemplifying embodiment, an apparatus, such as a node or userdevice, may include means for carrying out embodiments described abovein relation to FIGS. 2 through 7.

Processors 814 and 824 may be embodied by any computational or dataprocessing device, such as a central processing unit (CPU), digitalsignal processor (DSP), application specific integrated circuit (ASIC),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), digitally enhanced circuits, or comparable device or acombination thereof. The processors may be implemented as a singlecontroller, or a plurality of controllers or processors. Additionally,the processors may be implemented as a pool of processors in a localconfiguration, in a cloud configuration, or in a combination thereof.

For firmware or software, the implementation may include modules orunits of at least one chip set (e.g., procedures, functions, and so on).Memories 815 and 825 may independently be any suitable storage device,such as a non-transitory computer-readable medium. A hard disk drive(HDD), random access memory (RAM), flash memory, or other suitablememory may be used. The memories may be combined on a single integratedcircuit as the processor, or may be separate therefrom. Furthermore, thecomputer program instructions may be stored in the memory and which maybe processed by the processors can be any suitable form of computerprogram code, for example, a compiled or interpreted computer programwritten in any suitable programming language. The memory or data storageentity is typically internal but may also be external or a combinationthereof, such as in the case when additional memory capacity is obtainedfrom a service provider. The memory may be fixed or removable.

The memory and the computer program instructions may be configured, withthe processor for the particular device, to cause a hardware apparatussuch as network element 810 and/or UE 820, to perform any of theprocesses described above (see, for example, FIGS. 6 and 7). Therefore,in certain embodiments, a non-transitory computer-readable medium may beencoded with computer instructions or one or more computer program (suchas added or updated software routine, applet or macro) that, whenexecuted in hardware, may perform a process such as one of the processesdescribed herein. Computer programs may be coded by a programminglanguage, which may be a high-level programming language, such asobjective-C, C, C++, C#, Java, etc., or a low-level programminglanguage, such as a machine language, or assembler. Alternatively,certain embodiments of the invention may be performed entirely inhardware.

Furthermore, although FIG. 8 illustrates a system including a networkelement 810 and a UE 820, embodiments of the invention may be applicableto other configurations, and configurations involving additionalelements, as illustrated and discussed herein. For example, multipleuser equipment devices and multiple network elements may be present, orother nodes providing similar functionality, such as nodes that combinethe functionality of a user equipment and an access point, such as arelay node.

Certain embodiments may have various benefits and/or advantages. Forexample, certain embodiments permit light connected mode and associatedRRC savings while minimizing the impacts on network signaling. Certainembodiments can provide the RRC savings advantages of RRC idle mode whenmoving inactive across the last serving eNB and, whenever data needs tobe exchanged, the RRC signaling sent by the UE can be limited to this“Uu paging response” message for MT case. By so doing, certainembodiments can provide battery saving for devices which are batteryconstrained and which may need to exchange intermittent data whilemoving.

When applied to LTE, certain embodiments can avoid the need to definenew X2 paging procedure and principles, can avoid new buffering and dataforwarding constraints on the eNB, and can avoid increase of contexts inthe SGW. Certain embodiments can leverage eNB and MME implementationsthat have implemented the CIoT feature.

One having ordinary skill in the art will readily understand that theinvention as discussed above may be practiced with steps in a differentorder, and/or with hardware elements in configurations which aredifferent than those which are disclosed. Therefore, although theinvention has been described based upon these preferred embodiments, itwould be apparent to those of skill in the art that certainmodifications, variations, and alternative constructions would beapparent, while remaining within the spirit and scope of the invention.

1. A method, comprising: identifying, by a device, that a user equipmenthas left an area; and starting, by the device, a suspend procedure forthe user equipment based on identifying that the user equipment has leftthe area.
 2. The method of claim 1, wherein identifying that the userhas left the area comprises receiving a message which has been sent uponreceiving a message transmitted from a user equipment.
 3. The method ofclaim 2, wherein the received message is received over an X2 interface.4. The method of claim 2, wherein the received message applies to aninterface between two access nodes of a mobile network.
 5. The method ofclaim 2, wherein the message transmitted from the user equipment isautonomously generated by the user equipment upon detecting that an areaidentifier has changed.
 6. The method of claim 5, wherein the areaidentifier comprises at least one of an access node identifier or aradio access network area identifier.
 7. The method of claim 1, whereinthe area comprises a radio access network area comprising one cell or aplurality of cells in which light connected mode is permitted.
 8. Amethod, comprising: identifying, by a device, that a user equipment hasleft an area; and communicating, by the device, with an access node inthe area to inform the access node that the user equipment has left thearea.
 9. The method of claim 8, wherein the communicating comprisesgenerating a message upon receiving a message from the user equipment.10. A method, comprising: receiving, at a device, a first areaidentifier corresponding to a first radio access network area or a firstaccess node; receiving, at the device, a second area identifiercorresponding to a second radio access network area or a second accessnode different from the first radio access network area or respectivelydifferent from the first access node; determining, by the device, thatthe second area identifier is different from the first area identifier;and generating, by the device, an indication toward an access node basedon the determination.
 11. The method of claim 10, wherein the indicationcomprises a location report.
 12. An apparatus, comprising: at least oneprocessor; and at least one memory including computer program code,wherein the at least one memory and the computer program code areconfigured to, with the at least one processor, cause the apparatus atleast to identify that a user equipment has left an area; and start asuspend procedure for the user equipment based on identifying that theuser equipment has left the area.
 13. The apparatus of claim 12, whereinthe user having left the area is identified by receiving a message whichhas been sent upon receiving a message transmitted from a userequipment.
 14. The apparatus of claim 13, wherein the received messageis received over an X2 interface.
 15. The apparatus of claim 13, whereinthe received message applies to an interface between two access nodes ofa mobile network.
 16. The apparatus of claim 13, wherein the messagetransmitted from the user equipment is autonomously generated by theuser equipment upon detecting that an area identifier has changed. 17.The apparatus of claim 16, wherein the area identifier comprises atleast one of an access node identifier or a radio access network areaidentifier.
 18. The apparatus of claim 12, wherein the area comprises aradio access network area comprising one cell or a plurality of cells inwhich light connected mode is permitted.
 19. An apparatus, comprising:at least one processor; and at least one memory including computerprogram code, wherein the at least one memory and the computer programcode are configured to, with the at least one processor, cause theapparatus at least to identify that a user equipment has left an area;and communicate with an access node in the area to inform the accessnode that the user equipment has left the area.
 20. The apparatus ofclaim 19, wherein the communicating comprises generating a message uponreceiving a message from the user equipment.
 21. An apparatus,comprising: at least one processor; and at least one memory includingcomputer program code, wherein the at least one memory and the computerprogram code are configured to, with the at least one processor, causethe apparatus at least to receive a first area identifier correspondingto a first radio access network area or a first access node; receive asecond area identifier corresponding to a second radio access networkarea or a second access node different from the first radio accessnetwork area or respectively different from the first access node;determine that the second area identifier is different from the firstarea identifier; and generate an indication toward an access node basedon the determination.
 22. The apparatus of claim 21, wherein theindication comprises a location report.